Flow controlled water heater



Nov. 18, 1.941.

H. w. WILKINSON 2,263,227 FLow CONTROLLED WATER HEATER Y Filed March 5, 1940l I0 Z7 ff wl v3 ,d Z C j 'Z Zz L I l l a A ,l o 1e 12a a j@ 85 5G65 /ZZ 5.5 Z5 27 ,7r "="7v l Patented Nov. 18, 17941 FLOW CONTROLLED-WATER HEATER Harry W. Wilkinson, Mount Airy, Pa., assignor to John Wood `Manufacturing Company, Inc., Conshohocken, Pa., a corporation of Delaware v Application March 5, 1940, Serial No. 322,310 i 2 Claims. (Cl. 236-33) My invention is applicable to control a main burner which is part of a Water heater, by location of a thermostatic couple in such position that it is directly heated by the products of combustion from the burner. couple is a tube of copper or other metal having a high coefficient of expansion and which is a conduit through which the Water flows to a main heating coil in the heater. It is characteristic of my invention that operation of the burner is controlled by the now of water through that thermostatic tube. The flow of cold water through said thermostatic tube contracts the latter and causes the main burner to operate. The heating effect of the burner is stopped when the Water in One member of that K said thermostatic tube is heated to a predeteri mined temperature by said burner.

In the Aform of my invention `chosen for illustration, said thermostatic tube is U-shaped and has both of its ends rigidly rconnected with the casing of a valve which is mountedlexterior to the heater casing and controls the flow of fluid to said burner. The other member of the thermostatic couple is a rod which is substantially invariable in length under the temperatures to which it is subjected, but is rigidly :connected at one end with the bight of said tubular member of the couple and has its other end arranged to reciprocate in said valve casing in operative relation with said valve, `which is continually stressed toward its closed position by a springin said casing, but arranged to be opened by the thrust of said rod when the tubular member of the thermostatic couple is contracted by the flow of cold water therethroughat a predetermined l temperature lower than that at which the valve is permitted to be automatically closed by its spring. Said thermostatic couple is so positioned in the heater casing that it is continually subjected to the heat from the burner when the latter is ignited, so that when Water is not flowing through the tubular thermostatic member, it is expanded by the heat from the burner so as to permit the valve to remain closed by its spring.

In the form of my invention chosen for illustration, I have found it convenient to provide a pilot burner in lighting relation to the main burner in the heater so that a small liame may be continually afforded at the pilot burner to light the main burner when said valve is'opened by the aforesaid operation of the thermostatic couple. Moreover, I iind it convenient to associate With said burners in position to be heated by iliary valve controlling the supply of uid fuel to the `main burner, at the burner, so that While either burner is lit, said strip is expanded by heat and thereby flexed to open the auxiliary valve but, when the burner flamesrare extinguished that strip contracts and closes said auxiliary valve.

My invention includes the various novel features of construction and arrangement hereinafter more definitely specied.

The drawing is a fragmentary vertical sectional 4view ofY a Water heater casing and its appurtenances showing, somewhat diagrammatically, a convenient embodiment of my invention.

' In the drawing; gas or other fluid is supplied through the conduit I, the'valve casing la, and conduit IID to the main burner 2` under control of the thermostatic valve 3 which is continually 'pressed by the spring 4 toward its closed position. Said valve is arranged to be opened by thrust of the disk 5, left, against the snap spring 6 which is operatively connected with the valve 3 by the adjustable screw 3E. `Such thrust is effected by the thermostatic `couple member 1 which is substantially invariable in length under the temperatures to which it is subjected and mounted to reciprocate toward and away from said valve casing I a. Said rod is screw threaded at its end la, for adjustment inthe nut 'lbwhich is iixed in the bight of the U-shaped expansion tube 8 forming the other member ofthe thermostatic Vcouple and whichis expansible `and contractible in accordance with variations in the temperatures` to which the couple is subjected.

The ends of said expansion tube B are rigidly mounted in the fitting 8a which is detachably rigidly connected `with said valve casing Ia by any convenient means. The cold water supply conduit 9 is in communication withone end of said expansion tube 8 through said fitting 8a. The otherv end of said expansion tube 8 `is* in communication with the heating coil I0 through said fitting Ila and leads to means for dispensing hot water exemplified by the spigot I I.

The pilot burner I2 is supplied with the uid fuel through the conduit I3 which is conveniently branched from the main supply conduit I and controlled by the manually operative valve I3. When the fuel from the pilot burner I2 is lighted, its flame I2a is in heating relation with the bi- -netal thermostatic element I4 which is operatively connected by the stem I5a with the valve I5 controlling the inlet port 2a in vthe main burner 2. When thus heated, the unequal expansion ofthebi-metal components of the thermostatic strip I4 exes it to lift and open the valve I5 as shown, and it is maintained open as long as said element I4 is subjected to either the heat from the pilot burner flame I2a or the heat from the flames 2|@l of the jets of the main burner 2. Said burners 2 and I2, tube 8, and the heating coil I0, are preferably inclosed by the heater casing I1, leaving the valve casing Ia exterior thereto. The products of combustion from said burners, thus directed in maximum heating relation with said expansion tube 8 and coil I0, may be directed `from said casing through the flue I1a under control of the damper valve I'I-b and said flue is preferably connected to a. suitable chimney vent.

Said snap spring 6 is formed of initially plane sheet metal which is pressed to concave-convex form and normally set with its convex surface toward the thermostatic couple. Its perimeter is fixed in the circular frame 6a, Within the annuiar rim 6b on said frame, which is removably positioned in the valve casing Ia as shown. Said snap spring is so formed that it continually tends to return to its initial position and is only displaced to the opposite convexity shown when under pressure of the disk 5 when the latter is thrust to the left by the thermostatic couple member 'I 'as above described. I prefer to make that snap spring assembly as described and claimed in my co-pending application Serial No. 232,136 filed September 28, 1938, for Letters Patent of the United States for Improvement in thermostatic controls. Said application has matured into Patent #2,215,384, dated Sept.` 17, 1940. As thus made, the spring has three radial arms disposed in symmetrical relation with the axis of the saucer shaped frame Iia and the end of each of said arms is rigidly connected with said frame by respective screws Bc. After the spring 6 is thus secured. in its frame Ba the annular rim 6b is slightly distorted, by being bent inwardly atthe ends of two of said arms, whereby the spring 6 is subjected to compression edge- Wise toward its axial region and convexed outwardly from said frame toward the right as shown, with its axis in slightly eccentric relation to said frame. Said spring 6 is thus arranged to snap alternately, in opposite directions, transversely to its plane, in accordance with the pressure to which it is subjected on its side thus convexed. The spring 4 continually stressing said valve 3 toward said snap spring 6 facilitates the snap action of said spring to its initially conveXed position, when relieved of the pressure of the thermostatic member 1. However, any other suitable form of snap spring which is capable of the desired reversal under the described conditions of pressure upon the right hand face thereof shown may be employed.

The differential temperatures at which said valve 3 may be opened and closed may be Variably predetermined by the position to which the thermostatic rod l is axially adjusted by rotation of its screw threaded end Ia in the nut 1b. The extent to which the valve 2 is opened by the thermostatic couple is also variably determinable by the position to which the set screw 3ad is axially adjusted by its rotation in the stem of the valve 3.

I find it convenient to provide the valve casing le with the removable screw plug 4a as an abutment for the spring 4 and to provide the opposite side of said valve casing Ia with the removable cover plate Id, containing the stuiiing box Ic and to provide said cover plate with the truncated conical projection Ie in coaxial relation with the bearing If for the rod 'I to facilitate the precise location of the uid conduit fitting 8a, and to rigidly connect said iitting with said cover plate by two screws 8b, as shown in the drawing. However, other suitable means may be employed to support the thermostatic couple in cooperative relation with the valve controlling the supply of fuel to the burner 2.

Therefore, I do not desire to limit myself to the precise details of construction, arrangement, or method of operation herein set forth, as it is obvious that various modifications may be made therein without departing from the essential features of my invention as dened in the appended claims.

I claim:

1. In a water heater controlled by the flow of water from it; the combination with a fluid fuel burner; of a valve casing; a fuel supply conduit, leading to the burner through the casing; a valve in the casing, controlling that conduit; a spring continually stressing the valve toward its closed position; a thermostatic couple including a rod member substantially invariable in axial length by the temperatures to which the couple is subjected and mounted to reciprocate axially toward and away from the valve, respectively to open the valve and permit it to be closed by its spring, and having a screw thread at its end remote from the valve; a nut engaging that thread; a Water conducting expansion tube, bent to U- shape, forming the other member of the couple, and longitudinally expansible and contractible by the temperatures to which it is subjected, and having both of its end regions extending parallel with the rod, from a blight region between those ends which is rigidly xed to the nut; means securing both ends of the expansion tube in rigid relation with the casing, with that tube in position to be expanded by heat from the burner; a water supply conduit leading to one end of the expansion tube; a water discharge outlet leading from the other end of the expansion tube; and means for controlling the flow of water from the heater, through the expansion tube; whereby, differential temperatures at which the valve is respectively opened and permitted to close, may be variably determined by turning the rod in the nut, and the fuel valve is opened at the lower temperature, by contraction of the expansion tube, by cool Water therein, and consequent thrust of the rod toward the valve, and closed at the higher temperature, by its spring, when the rod is withdrawn from the valve by expansion of the expansion tube, by heat from the burner.

2. In a water heater controlled by the flow of water from it; the combination with a iuid fuel burner; of a valve casing; a fuel supply conduit, leading to the burner through the casing; a valve in the casing, controlling that conduit; a spring continually stressing the valve toward its closed position; a thermostatic couple including a rod member substantially invariable in axial length by the temperatures to which the couple is subjected and mounted to reciprocate axially toward and away from the valve, respectively to open the valve and permit it to be closed by its spring, and having a screw thread at its end remote from the valve; a nut engaging that thread; a water conducting expansion tube, bent to U shape, forming the other member of the couple, and longitudinally expansible and contractible by the temperatures to' which it is subjected, and having both of its end regions extending parallel with the rod, from a bight region between those differential temperatures at which the Valve is respectively opened and permitted to close, may be variab-ly determined by turning the rod in the nut, and the fuel Valve is opened at the lower temperature, by contraction of the expansion tube, by cool water thereimand consequent thrust of the rod toward the Valve, and closed at the higher temperature, by its spring, Whenrthe rod is Withdrawn from the Valve by expansion of the 10 expansion tube, by heat from the burner.

HARRY W. WILKINSON. 

